Texture Loss: Texture loss, also called style reconstruction loss, is proposed by Gatys et al. [1]}, [2]}, which can make the model reconstruct high-quality textures. The texture loss is defined as the squared Frobenius norm of the difference between the Gram matrices \(G_j^{\phi }(x)\)  of the output and the ground truth images:
\(\mathcal {L}^{\phi ,j}_{texture}(I_{SR},I_y)=||G_j^{\phi }(I_{SR})-G_j^{\phi }(I_y)||^2_F.\) 
